by Catalina Camia, USA TODAY

The congressman's office said in a statement that the allegation stems from a "Federal Election Commission reporting error" made more than a year ago by an accountant who was a campaign volunteer. Stockman's office said when the error was discovered six months later, the accountant was removed from his position and that the campaign committee has since been closed.

"My office is aware of and is cooperating fully with the Ethics Committee's preliminary inquiry into an FEC reporting error," Stockman said.

The independent Office of Congressional Ethics conducted an initial review of the Stockman matter and referred it to the full Ethics Committee.

The Houston Chronicle reported last year that two Stockman staffers were fired for making prohibited contributions to Stockman's campaign. The staffers had attributed the campaign donations to family members.

Stockman's office said in its statement Friday that the election commission did not levy a fine because the congressman took corrective action.

Stockman lost a Senate primary in March to incumbent Sen. John Cornyn, the No. 2 Republican leader. The congressman was re-elected to the House in 2012, after initially serving one term in the mid-1990s.